Semi-automatic telephone-exchange system



L. POLINKOWSKY.

SEMI-AUTOMATIC TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED ocT.23, 1918.

1,400, 1 8 1 Patented Dec. 13, 1921.

5 SHEETSSHEET I.

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L. POLINKOWSKY.

SEMI-AUTOMATIC TELEPHONE EXCHANGE SYSTEM.

' APPLICATION FILED 00123, 1918.

Patented Dec.13, 1921.-

5 SHEETS-SHEET 3- WW All/y L. POLINKOWSKY. E SEMI-AUTOMATIC TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED OCT-23, I918.

Patented Dec. 13, 1921 s SHEETS-SHEET 4. a L

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L. POLINKOWSKY. SEMI-AUTOMATIC TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED OCT-23. 19I8.

1,400, 18 1. Patented 9%..13, 1921.

' 5 SHEETS-SHEET 5.

.UNITED STATES PATENT OFFICE.

LIPA POLINKOWSKY, OF LONDON, ENGLAND, ACSIGNOR "l'O VJESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. L, A. CORPORATION OF- NEW YORK.

SEMI-AUTOMATIC TELEPHONE-EXCHANGE SYSTEM.

Application filed. October 23, 1918.

T 0 all whom it may concern Be it known that I, LIPA POLINKOWSKY, a citizen of Russia, residing at 70 Westbourne Terrace, Hyde Park, London, England, have invented certain new and useful improvements in Semi-Automatic Telephone- Exchange Systems, of which the following is a full, clear, concise, and exact description. This invention relates to semi-automatic telephone exchange systems and more particularly to a telephone system in which a subscribers line is reached over switches the circuits of which are extended to operators positions and the operators given full supervision to'the connection during and after the establishment thereof and they also control the release of the connection. In systems of this character arrangements are known by which a call incoming on a cord of an operators position can be helped out from a neighboring position. When helping out, a neighboring operator communicates with the calling subscriber and sets up the switch of the cord under the control of the number keys of her position. The supervision of the con nection and all operations in connection therewith, such as forced release, bringing the same calling line on the same cord a secend time, the bringing of the switches in a hold-over position, etc, is left under the control of the operator of the position on which the call appeared. In systems of this character the cords of a number of operators are distributed so that they have access to a large number of subscribers lines, and, when a call on an operatofls position is awaiting attention, the. remaining free cords of this position are placed in inoperative condition for a predetermined length of time, usually the time necessary for the operator to attend an awaiting call, leaving the way open for further calls to go to free operators positions.

When an operator leaves her position, the cords of sucli position are likewise put out of service so that no calls can come in on such position.

When the traflic slacks on so that a few operators are sufficient to maintain service, it becomes desirable to provide means which enables these few operators to give full and efficient service.

feature of this invention, therefore, is an arrangement of circuits and apparatus by Specification of Letters Patent.

Patented Dec. 13, 1921.

Serial No. 258,342.

which the cords of a vacant neighboring p0- sltion are kept in service by being concentrated into a position which we have termed a concentration position. The subscribers lines beingdivided into a number of groups, eiiic1ent service can be given if the number of cords that each such operator can control is increased.

It is essential that the concentration operator have the same kind of manipulation for calls coming in on the cords of her position and on calls coming in on the neighboring positions.

A further feature of the invention, therefore, is an arrangement of circuits and apparatus which provides that the concentration operator in giving service to a call arriving on a neighboring position may use the common equipment provided on her own position.

A particular feature of the invention, therefore, is an arrangement of circuits and apparatus for connecting the release and listening keys, etc, on the neighboring position with the common keys or like equipment on the concentration position.

A further feature of the invention relating to the above described feature provides that an operators position used ordinarily for handling the cords of this position may be converted into a concentration position by means of switches brought into operation by the use of concentration keys, which switches provide the necessary changes in thecircuits of the neighboring posit-ion.

Still another feature of the invention and one related to the above described features provides that the switches which convert the circuits of'the neighboring position will not be operative unless the plug of the operators telephone set is withdrawn from the jack of such position.

Still another feature of the invention is the provision of means for rendering inop erative both on the concentration position and the neighboring positions the apparatus which holds the free cords of a position in operative condition while a call is awaiting attendance, when concentration has taken place.

Certain other inventive features shown and described herein are not claimed herein but are to be claimed in other applications to be filed assigned to the present assignee.

Figure 1 shows a first line finder.

Fig. 2 shows a cord circuit comprising a second line finder and a first group selector.

Figs. 3, 4 and 5 show diagrammatically an oper'ators concentration position, with the associated neighboring positions.

The system disclosed as embodied in the present invention will be best understood from a description of the operation thereof.

The subscribers lines are connected to groups of first line finders and these in turn to groups of second line finders or cords. The cords which have access to the same first line finders are distributed in small groups on a number of operators positions. If a call arrives on a osition the remaining free cords of this position are kept isolated for a predetermined length of time and are then released. If an operators position is vacant the cords on this position are kept isolated.

Each operators position is provided with two registers called A and B registers with which the cords of her position are brought in temporary connection, giving privilege to the A register when both registers are free.

For better understanding the establishing and supervision of a connection will first be described when the concentration service is not in use. Each cord (Fig. 2) has two sequence switches 220 and 250 for establishing in sequence the different circuits, and a searching sequence switch 330, Fig. 4, with which a connection with a free register of the home or a neighboring position can be obtained. If the A and B registers of the home position are not accessible the cords can obtain a connection with the A or B register of the righthand or lefthand operators position provided these registers are free and the neighboring operator is in a position to help out when the neighboring operator only receives from the subscriber the wanted number and depresses on her position the number keys. After the selection under the control of a register of the neighboring position has been completed the supervisionof the connection, the release, listening in, forced release, and so on, are under the control of thehome position.

During the concentration services the complete supervision of the connections on the cords of one or both neighboring positions is accomplished by the operator on the concentration position in using the common keys, etc., on this position. A special sequence switch 480 Fig. 3 is provided to concentrate the supervision of the cords of the lefthand position, whereas a similar sequence switch 580 Fig. 5 serves for the righthand position, which in Fig. 4 is shown as a semi- B position handling calls incoming from a distant manual exchange. To enable a concentration position to handle during the night the trafiic from a large group of subscribers, the cords on such a position have access to different first line finders than the ing relays 204 which are energized and provide over their front contacts in parallel a circuit for the energization of thepower magnets 211 of the free first line finders in the group. Each individual circuit is closed over the back contacts of the corresponding test relay 212 and the disconnecting relay 213. The brush carriages of the line finders rotate in a well known manner with the brushes over the terminals of the subscribers lines. 'When the test terminal 210 of the calling line, on which a potential has been created, is reached by a line finder, the lefthand high resistance winding of test relay 214 is energized in a circuit containing the terminal 210, lefthand back contact of relay 213 and the winding of relay 212. Relay 214 brings, over' its front contact, its righthand low resistance winding in parallel to its high resistance winding and the terminal 210 is so made busy. Relay 212 when energized disconnects on its back contact the power'magnet 211 and closes over its front contact a circuit for the energization of the holding magnet 215 and the common starting relays 216 while a potential is created on terminal 230. The relays 252 of the free cords which have access tothese first line finders are now energized in a circuitcontaining contact 253 bottom of the sequence switch 250, conductor 301, contact 352 of the sequence switch 350 which controls in a well known manner the time distribution on the operators position conductor 302, the common guarding relay 219 and the front contacts of the common starting relays 216.

A circuit is then established for the energization of each power magnet 261 ofthe taining contact 255 bottom of sequence switch 250, conductor 303, contact 353 of sequence switch 350, conductor 304, righthand high resistance winding of relay 264, contact 256 bottom of sequence switch 250, terminal 230,

resistance 217, front contact of relay 212 and back contact of relay 213. Relay 26 connects its lefthand low resistance winding over its front contact in parallel to its high resistance winding and so makes the terminal 230 busy. When contact 259 of the second line finderbrush carriage is opened the circuit is extended to the winding of relay 262 which is then energized and provides a circuit for the energization of sequence switch 250 over "front contacts or relays 252 and 262 and contact'257 bottom. In parallel to sequence switch 250 is connected over sequence switch contact 260 the hold ng magnet 265 of the line finder, whichis energized and the brush carriage is arrested and sequence switch 250 starts from position 1 and moves under the control of its local contact 251 into its position 4. In parallel to magnet 265 is also connected over conductor 305 relay 3&9 which energizes and causes the energization of sequence switch 350 in a circuit over its contact 357 top, contact 593 of sequence switch 580,contact 93 of sequence switch and front contact of relay 349. The timing sequence switch 350 tarts from position 1, isolating thereby on contacts corresponding to contacts 352 and 853 the remaining free cords of theposition, and completes a cycle operation under the control oi an interrupter 376 after the lapse oi a predeterniined length of time, whereby this 7 time is in the wel lrnown manner nrolonsed if relay 354 or 355 is energized. In posi tion 2 of sequence switch'250 relay 252 maintained energized in a local circuit over contact 269 top of sequence switch 250, conact bottom of sequence witch 220 and each contact of clearing-out relay 242.

When the sequence switch 250 passes to tween positions 2 and 3 a circuit is established over sequence switch contact 258 top, lefthand back contact of release relay 263, contact 266 h ttoni of sequence swi ch 250, Contact 222 bottom of sequence switch 220 to the magnet of this sequence switch, which energizes, starts from position 1 and moves unccr the control of its local contact 221 into position 4. When sequence switch 220 reaches ocsition 2 a circuit is establisheu from ground over contacts 258 top of se quence switch 250, contact 223 top of e quence swtch 220, right hand back contact of metering-hindering relay let hack contact of holdover relay 225, in

1 connecting relay 221 termi l 228, 'l and winding of relay 21 5 terminal 218 cut-off relay 207 i the suhscribers line. Relays 207, 213 and. 22? are thereby energized. The line rela 291 is causingthe deenergiuation oi the starting of the energized and the free first line finders are thereby de iree first line finders are nnders in the group are so the test relays 264C and cord in question are thereby de- Th lert hand windings of the 7 229 and the supervisory reconne ted over contacts 232 v f seqence witch 220 and l oth rront contacts of. relay 227 to the callin-' v station, Relay 231 is there F ergized. In position 1- of the sequence lamp 270 is lighted in includinc' the pilot relay 358, conr 306, contact 266, top oi sequence oth hacl: contacts of relay 7 hequence switch contact 255 top, and 270 indicates a waiting call on the o1)- s position.

2 of sequence switch 250 a n. relay 20 .2;

ich secs able too 1 lish conhec Z bottom prorid the hio'h resis O ov r contact 5 co'i'iductor 80% to ground. Assuming 1 t the 1" gister oi the horns position is yitch 330 reaches its :EOSlti t e energized in a bottom of '09, contact 530, right lay 381, contact e82 of fine e which controls the 3. ct oi ols the B a 22 i briiigs over to its high resistdingg and 1 he magnetic energization of clutches of the number keys on the operators position as well as the setting up of the registers according to the depressed number keys. The lefthand high resistance winding of relay 381 is connected over its lefthand front contact and over contact 386' of the sequence switch 380 in series with its righthand winding, and when the sequence switch 380 leaves position 2 and its contact 382 is opened both windings of relay 381 are maintained energized in the circuit described over conductor 309. Relay 262 when energized disconnects sequence switch 330 which when its local contact 331 is also opened is arrested in position 7 whereas the sequence switch 250 is again energized in the circuit over front contact of relay 262, as has been described, starts from position 4 and moves over position 5 into position 8.

When sequence switch 250 passes position 6 a circuit is established for the energization of sequence switch 220 over contact 234 bottom, contact 271 top of sequence switch 250 and righthand back contact of relay 225. Sequence switch 220 starts from position 4 and moves into position 5 in which the calling lamp 270 is connected over sequence switch contact 226 bottom with a common interrupter 236 displaying a flashing signal before theoperator. Over the contacts 232 and 233 of sequence switch 220, conductors 313 aud3l4, and the contacts 334 and 335 sequence switch 330, is established a bridge to the calling line including the conductors 378 of the operators telephone,

whereas the current supply for the calling station is maintained over sequence switch contacts 237 bottom and 238 top, and the contacts of rest on the listening key 239.

The circuit of relay 381 is in position 6v and 7 of sequence switch 250 connectedto ground over contact 333 and contact 272 bottom, and in position 7 to 12 over contact 268 top of sequence switch 250, lefthand back contact and low resistance winding of relay 224. Belay 224 remains thereby deenergized. The operator then communicates with the calling party and having ascertained the number wanted depresses the corresponding number keys of her position, after which sequence switch 380 of the register advances in a well known. manner into a position to enable the control of the fundamental circuit and the counting relays of the register. A circuit is thereby closed from round over front contact of relay 381,

contact 388 of sequence switch 380,contact 338 bottom of sequence switch 330, conductor 312, contact 241 bottom and sequence switch 220, which is energized, starts from position 5 and moves into position 8. 236 is now disconnected on sequence switch contact 226 from the lamp 270 and is connected to the ringing lamp 240, which dis- Tnterrupter plays flashing signal indicating the progress of selection.

The fundamental circuit containing the stepping relay-324 is traced from ground at sequence-switch contact 387 bottom winding of relay 324, the back contact of the last or zero counting relay 320 and is extended first to relay 252 of the cord over contact 336 bottom of sequence switch 330, conductor 310, and "contact 269 bottom of sequence switch 250 to winding of relay 252 and grounded battery. The stepping relay 324 and the relay 252 on thecord are thereby energized. The control of the counting relays on the register circuit over the conductor 321,-contacts 322 of a corresponding register and contact 389 bottom of sequence switch 380 is well known and generally similar to the control disclosed in U. S. Letters Patent, N 0. 1,141,352 of F. R. McBerty, and need not be specially considered. Relay 252 provides a circuit for the energization of sequence switch 250 over its contact260 bottom, back contact of relay 262 and front contact and grounded armature of relay 252. The sequence switch 250 starts from position 8 and moves into position 9 in which the trip spindle magnet 273 isenergized in a circuit over contact 274 bottom of sequence switch 250 and front contact of relay 252. The trip spindle rotates and the closing of the trip spindle contact springs 275 provides over the top spring and sequence switch contact 253 top the'short circuiting in a well known manner of the stepping relay 324 of the fundamentalcircuit. After the counting relays have been energizedin succession in the first series of impulses, the fundamental cir contact 257 top and back contact of relay 252.

he sequence switch 250 starts from position 9 and moves into position'l0 in which relay 252 is again energized in a circuit over contact-269 top of sequence switch 250 and contact 241 top of sequence switch 220, conductor 312, contact 338 bottom'of sequence switch330, contact 388 of sequence switch 380 and front contact of relay 381'. In position 10 of the sequence switch 250, the power magnet 281 of the brush carriage of the group selector is energized in a circuit over sequence switch contact 254 bottom, back contact of relay 262 and front contact of relay 252 and the brush carriage is moved with the brushes along the terminal row which corresponds to the position of the trip spindle, whereby the test relay 264 searches for a free trunk to a second group selector. .Vhen such a trunk is found the relay 264 is energized in a circuit from ground over back contact of relay 225, contact 271 bottom of sequence switch 250, righthand high resistwinding of relay 264, sequence switch contact top and the test terminal 27 6 of the free second group selector. The winding of relay 262 is brought over the front contact of relay 264 and its lefthand low resistance winding in parallel to its high resistance winding and the trunk to the second group selector is so made busy. The power magnet 281 is thereby disconnected on the back contact of relay 262 whereas the sequence SW1tCl'I25O is energized in the circuit over its contact 257 and front contact of relay 262. In parallel to the sequence switch is connected the holding magnet 285 of the group selector over sequence switch contact 277 bottom. The brush carriage is arrested and sequence switch 250 is started from position 10 and moved over osition 11 into position 12 in which the fundamental circuit is now extended over the contacts 278 bottom and 27 9 bottom of sequence switch 250 to the second group selector.

The fundamental circuit now includes conductor 311, contact 337 bottom and contact 387 top of sequence switch 380. After the second group selector and the final selector have been set up in the well known manner under the control of the register and sequence switch 380 is restored to its position of rest, sequence switch contact 386 is opened and relay 381 is denergized. The circuit of relay 252 is thereby opened and sequence switch 250 is energized inthe circuit over contact 257 and back contact of relay The sequence switch 250 starts and moves from position 12 into position 14 in which the connection to the register is opened on the sequence contacts 278 and 279 and the brushes of the first. group selector are ex: tended to the righthand winding of the repeating coil 229 and the supervisory relay 242. As soon as the sequence switch of the final selector, in finding the wanted line free, passes the position in which the busy condition of a line is transferred, in bridging both wires at the final selector to the first group selector, relay 242 is energized and provides the energization of sequence switch 220 over its contact 222 top and front contact of relay 242. Sequence switch 220 starts from posi-. tion 8 and moves into position 9. After the bridge on the final selector is opened relay is deenergized and sequence switch 220 is energized in a circuit over contact 234 top and back contact of relay 242. The sequence switch 220 starts from position 9 and moves into position 11 in which the ringing lamp 240 is connected in a circuit over sequence switch contact 2&3 t p nd ac ontact f relay 242. WVhen the called subscriber answers and the final selector is advanced to the talking position in which a through connection is established with the line, relay 242 is again energized and sequence switch 220 is energized in the circuit described over the front contact of relay 242, starts from position 11 and moves into position 14.

When the conversation is finished and the clearing-out signals 245 and 235 appear before the operator, she depresses the release key 280, and the lefthand winning of release relay 263 is energized in a circuit over middle contact of key 280, contact 24 of sequence switch 220 and back contact of relay 231. Relay 263 maintains its energization in a circuit over contact 255 top of sequence switch 250, righthand front contact and righthand winding of relay 263. The sequence switch 250 is energized in a circuit over the lefthand front contact of relay 263 and sequence switch contact 258 top. The sequence switch 250 starts from position 14 and moves into position 17. When reaching position 15 a circuit is established over righthand back contact of relay 225, contact 271 top of sequence switch 250, contact 234 bottom and magnet of sequence switch 220 which starts from position 14 and moves into position 1. In leaving position 15 the circuit for the cut-off relay 207 is disconnected on sequence switch contact 223 from ground and is temporarily connected to the metering battery so that the meter 208 on the subscribers line is operated.

When sequence switch 220 reaches position 18, relay 252 is again energized in the circuit over sequence switch contact 243. Sequence switch 250 is energized in the circuit described over front contact of relay 252 and back contact of relay 262, the sequence switch 250 starts from position 17 and moves into position 18 in which the power magnet 281 is again energized in the circuit as has been described, and the brush carriage of the group selector is moved to its position of rest. In reaching this position its home contact 289 is closed and relay 262 is energized in a circuit over contact 289, sequence switch contact- 277 top and holding magnet 285, disconnects on its back contact the power magnet 281 and provides over its front contact the energization of sequence switch 250. The brush carriage is arrested whereas the sequence switch 250 moves into position 1.

If the called line is found busy the sequence switch of the final selector remains in the busy position, relay 242 remains energized and sequence switch 220 is held in position 9 in which the supervisory lamp 235 is connected in a circuit over sequence switch contact 248 top to a busy flash interrupter 246, Qyer sequence switch con- 19 scriber.

tact 237 top and 238 bottom is connected thereby the secondary winding of a common busy tone coil 247 in bridge to the calling line. The operator, noticing'the busy flash, depresses her listening key 239 and communicates with the calling party. 'When the listening key is depressed a circuit is established Over the bottom contact of the listening key containing the righthand winding of relay 225, wire 315, and the windings of relays 360 and 361. Relay 225 remains thereby deenergized whereas relay 360 dieconnects the operators telephone from the leads over which automatic connections with other cords are made, as described, and connects her telephone over conductors 318 and 319 with the listening key. Relay 361 disconnects the test circuit for the registers and hinders that cord carrying a call that would otherwise obtain a connection with a register during the time the operator communicates over a listening key with another sub- After the subscriber restores his receiver and relay 231 is deenergized the operator depresses the release key 280 and causes the energization of relay 263, as has been described. Sequence switch 250 starts from position 14: and moves into position 17 and when after leaving position 16 sequence switch contacts 273 and 279 are opened, relay 241-2 is deenergized and sequence switch 220 is energized in the circuit over the back contact of relay 242, starts from position Qand moves over positions 11 and 15 into position 1. Sequence switch 250 therefore reaches position 17 before sequence switch 220 passes position 15 and in opening its local contact 251 in position 17 the circuit for the cut-off relay 207 and relays 213 and 227 is O3GIIG and these r lays are deenergized. Over the left hand back contact of relay 227 a circuit is established containing the right-hand winding of relay 22a and the sequence switch cont-act 233. Relay 224i is energized and maintains its energization over its lefthand front contact and lefthand winding, whereas on its righthand contact and contact 223 bottom the connection to the metering battery 359 is opened. The circuit to the cut-off relay 207 and relays 227 and 213 is thereby immediately restored on the righthand front contact of relay 224: and when the sequence switch 250 reaches position 18 the lefthand winding of relay 224 is short-circuited on sequence switch contact 272, relay 22 1 is deenergized and the disconnection is so completed without metering.

If the connection is given up when the sequence switch 220 of the cord is in the ringing position 11, the release proceeds in the same way as described, sequence switch 250 still reaching its position 17 and opening'the circuit for relay 227 before sequence switch 220 leaves position 15.

The release of the connection can be started at any moment during the progress of the selection. 2 In the first instance a premature release without the aid of the operator is possible in. position 2 of sequence switch 250 if afterthe second line finder has obtained a connection and the sequence switch-250 has been started whereas relay 2641 fails to hold its energization during the time the sequence switch passes over position 2, whichmay be the case if the operative windings of two test relays 26 i become energized at thesame moment and cause the operation of the corresponding relays 262. As soon asthe sequence switch 250 leaves position 1, the high resistance winding of relay 264 is disconnected on contact 255 and the low resistance winding of this relay is able to maintain its energization only if it is alone in circuit with a terminal 230 but if two such windings should be connected in parallel the relays open their front contacts and cause the deenergization of the corresponding relays 262.

The lefthand' winding of relay 263 is thereby 'and sequence switch 330 is operated and moved from the position in which it happened to stay into position 13 in which no connection witha register is possible, after which sequence switch 250 is energized over lefthand front contact of relay 263, sequence switch contact 253 bottom and contact 332 top of sequence'switch 330.

The depression of-the release key 280 remains without effectif relay 231 is energized over the calling line, and, if for any reason the operator has to release a cord on which the relay 231'is energized, she first depresses release key 280 and then fora short moment the forced release key 375. Relays 362 and 263 are then energized in a circuit over the righthand contact of the forced release key 375, back contact of relay 363, lefthand winding of relay 362, conductor 316,1efthandcontact of release key 280, sequence switch contact 282 bottom, middle contact of release key 280 and lefthand winding of relay 263 to grounded battery. Relay 362-after opening its back contact removes the short-circuiting ofthe righthand winding of the relay 363 which is new energized over the left- During such a release the se-' hand contact of the forced release key 375, maintains the energization of its lefthand winding in a circuit over its lefthand front contact and the righthand contact of the forced release key and disconnects the lefthand winding of relay 362 from the key. The energization of relay 362 is now maintained over both its windings in series and its front contact.

To bring in the same call a second time on the same cord the operator depresses the release key 280 and the forced release key 375 and maintains both keys depressed until the sequence switches of the cord return first in their position of rest and are then again started, as will be described. Then sequence switch 250 reaches position 15 the righthand winding of relay 224 is introduced in the circuit of relay 362 over sequence switch contact 282 top, whereas the lefthand winding of relay 263 is disconnected. The slow to release relay 362 remains thereby energized. Relay 224 is energized, disconnects the metering battery 359 and maintains itself locally energized, as has been described. The cutoff relay 207 of the subscribers line, relay 213 of the first line finder and relay 227 of the cord are thereby maintained energized during all the time of the release in the circuit over the righthand front contact of relay 224. When sequence switch 250 during such a release reaches position 1, it is energized in a circuit over righthand front contact of relay 363, conductor 317, righthand contact of release key 280 and sequence switch contact 260 top and the sequence switch 250 starts from position 1. When the sequence switch 250 leaves position 2. contact 282 is opened for a comparatively long time and causes the deenergization of relay 362. Relay 263 can therefore not become energized when the sequence switch contact 282 bottom is closed and sequence switch 250 is arrested in position 4, whereby sequence switch 230 searches for a new connection with a register. As soon as the lamp 270 lights, as has been described, the operator trees the keys 280 and 375. Together with the energization of sequence switch 250 in position 1 relay 349 is also energized, as has been described, and sequence switch 350 is started to isolate thereby the free cords of the position.

Though the metering or" a non-established conversation is hindered automatically, as has been described, the operator can, under special circumstancesi'or example, in the case of subscriber complaining of having received a wrong connection-hinder the metering in depressing the common metering-hindering key 364 on her position, together with release key 280 of the cord, whereby key 364 must be first depressed. The metering battery 359 is disconnected during the time sequence switch 220 moves over positions 16 to 18.

If a disturbance occurs in the the cord or in the selectors co it, the operator is able to hold used for the connection by depressin r the holdover key 365 together with the lis g key 239 of the cord. The high resistance windings of relays 360 and 361 are thereby shunted by a. low resistance 366 and the righthand winding of relay 225 is energized. The circuit for the cut-oil relay 207 of the subscriber line is opened at the leithand back contact of relay 225.. whereas the lefthand winding of this relay is maintained energized in a holding circuit over its lefthand front contact together with th over lamp 244. In opening its "i back contact the lefthand winding 0 264 is disconnected and the connect with. a free second selector is hindered in case such a connection has not yet been obtai ad and in the closing of its righthand iio t contact is caused the energization of relay 242 so that sequence switch 220 is advanced into position 14. Assuming that the holdover started when sequence switch 220 was in position 8, the sequence switch 220 which is energized in the circuit over Eli: con '-t of relay 242 and contact top will t fore reach position 9 before sequence switch 250 1s 1n position 14 and circuit is then sequence closed over contact 222 bottom of switch 220, contact 226 bottom switch 250, back contact or re ay sequence switch contact 258 top to Sequence switch 220 therefore in in advances over position 9 into position 11 where the circuit maintained closed over front contact of relay Sequence switch 220 therefore advances into position 14. \Vhen the quick-to-release rel: is deenergized on opening of the is hand back energized over the letthand back contact or relay 224. a described. On the lettaand back cc of relay 224 is opener the holding if relay 381 or" the regis er, should th start before the selc i register is then restored as de the rlghthand back contact 0' holding circuit is closed for the si contact of relay 225, relay 224 is lease relay 213 containing the "w relay 231, sequence switch contact of relay 227', terminal 2- O, i ithand winding of relay 213. back contact of relay 214 and the winding of relay 212. Relay 231 is thereby energized and no lam: signal is dispiayed before the oper itiou, whereas the potential or terminal 2M) corresponds to a busy poten al, so that no sec- 0nd line finder can be arrested on this first line finder, which 18 held on the ter inals of the calling line wlthout making the line busy.

The calling subscriber can then initiate a new call. The troubleman observing the lamp 244 lighted investigates the train of switches used for this connection and after having located the troublesome switch, the connection is released on depression of key 280 on the operators position. The restoration of the switches can also take place if the troubleman closes mechanically the local contact 251 of sequence switch 250.

If the A register of the position is engaged but it sequence switch 380 is in positions 7 to 18, the B register can be selected. by a cord, in which case-when the sequence switch 330 is rotating relay 264 can become energized in a circuit over contact 339 bottom of sequence switch 330, lefthand wind-- ing of relay 39]., contact 392 of sequence switch 390 of the B register, contact 384 of sequence switch 380 of the A register and back contact of relay 361. The sequence switch 390 is energized in a circuit over left hand front contact of relay 391 and sequence switch contact 395. The sequence switch 390 starts from position 1 whereby the righthand high resistance winding of relay 391 is maintained operated over its righthand front contact and sequence switch contact 396 as soon as contact 392 is opened. After the number keys of the position have been depressed and the B register has taken a corresponding position, sequence switch 390 moves in a well known manner into a -posit1on 1n which the A register 1f free can be taken for a new call, whereby its testing circuit i now closed over contact 394 of se quence switch 390. The different circuits between the cord and the B register are made over the corresponding contacts 335, 340, 341, 342- and 343 of sequence switch 330 in positions 2 or 8.

If the A and B registers of the operators positions are both engaged but the A register of the lefthand neighboring position is free, a connection with this register can be initiated over the corresponding top contacts 333, 334, 335, 336, 337 and 338 of sequence switch 330 in its position 3 or 9. The arrangement to extend the test circuits of the registers of the neighboring positions to the contacts of the sequence switch 330 is well known and is therefore not shown on the drawing. A call so extended to the register of a neighboring position brings the telephone of the operator in connection with the calling line, and after obtaining the number of the wanted subscriber, the neighboring operator in depressing her number keys provides the control of the selection of the switche from her register, after which the register is given free and the supervision of the call is left in the hands of the posi tion to which the cord belongs.

7 If the operator leaves her position. and

withdraws the plug from the telephone jack,

the-timing sequence switch 350 isenergized over sequence switch contacts 357 top and moves from position 1 into' position 12, where it remains, keeping all cords isolated.

If the traffic is largely reduced and especially during the night, the calls are handled only on concentration positions. For concentration services key 367 is depressed, and assuming that the lefthand neighboring position is vacant, a' circuit is established over the top contact of telephone jack456 on the neighboring position, lefthand contact of key-367, contact 482 bottom and magnet of sequence switch 480. The sequence switch is energized, starts from position 1 and moves under the control of its local contact.

481 into position 9 in which a number of circuits are prepared. On contact483 bottom of sequence switch 480 conductor 408 is disconnected from the metering battery on the neighboring position and is connected over the top of this contact to the non-metering key 364 and the metering battery 359 of the concentrationposition. On

contact 487 bottom of sequence switch 480 the conductor 415 of thelistening keys of the neighboring position, is disconnected from this positionand con'nected over the topof this contact to conductor 315 and key 365 of the concentration position.- On contacts 484 and 485 of sequence switch 400 the common leads 418 and 419 of the listening 7 keys of the neighboring position are con.- nected with the corresponding leads of the listening keys of the concentration'position. The conductor 416 of the lefthand'contacts of the release keys on theneighboring position is disconnected on contact 488 bottom of sequence switch 480 from the forced release key of this position and connected-to conductor 316 and the relay 3620f the forced release key 375 of the concentration position,

whereas on contact 439 of sequence switch 480 the conductor 417 c from the lefthand contact of the release keys is disconnected from the neighboring position and connected to conductor 317 and the front contact of relay 363 of the concentration position. Conductor 406 of th callinglamps of the cords is disconnected on contact 490 of sequence switch 480 from the pilot relay of the neighboring posltion and connected to the pilot relay 358. On contacts 491 and 492 of sequence switch 480 are the test circuits for the A, respectively B, register, comprising the relays381, respectively391, of the con-' centration position, connected to the searching sequence switches 430 of the neighboring position sothat such a connection need not be established over the helpingoutkeys (not shown in the drawing). On sequenceswitch contact 493 the circuit for the starting of the timing sequence switch 350 of the con centration position is opened so that when a call comes 1n andrelay 349 is energized, the

cords of this position are not isolated. In a similar way the circuit to start the timing sequence switch 450 on the neighboring position is opened on contact 494 of sequence switch 480, whereas on sequence switch contact 486 the connection of the contacts 432 of the searching sequence switches 430 on the neighboring position is disconnected from ground and brought under the control of contact 587 of sequence switch'580. Se

quence switch 450 of the neighboring position is energized in a circuit over contacts 457 bottomand lefthand contact of night concentration service key 367, starts from position 12 and moves into''- position -1. Through the opening of lefthand contact 01" rest of key 367 the energization of sequence switch 450 in its position 1 over the top contact of the telephone jack 456 is hindered and sequence switch 450 remains in its position 1 in which the corresponding contacts 452 and 453 for the power magnets of the line finders and the test relays areclosed.

Calls arriving on the cord of the lefthand neighboring position are now automatically extended to the registers of the concentration position and are handled in exactly the same manner ascalls arriving on a cord of the concentration position. The different circuits, such as the fundamental circuit, etc., between a cord of a neighboring position and the register of the concentration position are arranged over corresponding contacts of the searching sequence switch 430 in its positions '5 or 11 for the A register, respectively 6 or 12 for the B register.

In an exchange of medium size a night operator could also handle the trafiic incoming from a distant manual board, calls from which in the daytime are taken care of on semi-automatic B positions. For this purpose the A and B positions are preferably so arranged in a row that for night services the position is selected to which one neighboring position is an A position and the other is a B position. To the righthand side of Fig. 3 is indicated a B position on which calls from a manual A board arrive, so that if both neighboring positions are vacant the night operator is able to handle over the lefthand position and her home position calls initiated in the semi-automatic exchange, and over the righthand position calls arriving from a manual A board. The service of a B position is such that the A operator on the manual board communicates with the semi-B operator over an order wire, the operator names a free trunk and assigns it through the depression of anasslgnment key belonging to the incoming end of the trunk which is connected to a first group selector, the sequence switch of which obtains a connection with a free register of the B position.

In depressing the night concentration service key 368, Fig. 5, the neighboring B posi tion being assumed vacant, concentration sequence switch 580 is operated in a circuit over contact 582, the righthand contact on key 368 and the top contact of the operators telephone plug 556. Sequence switch 580 starts from position 1 and moves into position 9, making the following changes in the circuit of the B position-on sequence switch contacts 584 bottom and 585 bottom the leads of the order wire 570 from the distant exchange are disconnected from the B position and brought in connection over the tops of the same sequence switch contacts with making contacts of keys 369. In bridge to this connection is also placed the right-hand winding ofrelay 371. Over sequence switch contacts 586 the conductor which connects the contacts'332 of the searching sequence switch 330 of the cord of the concentration position is disconnected from ground and connected to a making contact on key 369.

n sequence switch contact 587 the contacts 432 of the searching sequence switch 430 of the lefthand neighboring A position are dis connected from ground and connected to a further making contact of key 369, and on sequence switch contact 588 a similar circuit is established for the contacts 532 of the searching sequence switches 530 on the righthand neighboring B position. On the sequence switch contacts 591 and 592 the corresponding sequence switch contacts of the searching sequence switches 530 and the B position are connected to the test circuits of the A and B registers of the concentration position.

Since the service of a B position is different from that on an A position in that the B operator assigns the trunk, whereas on an A position the connection with the operators telephone is'made automatically as soon as the operators position is free, the night concentration operator regulates the service by means of the key 369 and can handle the different calls in succession. If there are no local calls and an order wire call arrives, the operator throws the key 369 so as to operate its lower making contacts, whereby her telephone is connected over the making contacts of this key and over the sequence switch contacts 584 and 585 to the order wire, whereas on the lower rest contacts of this key the connection of her telephone to the cords of the A board is disconnected.

. obtains a connection with the A or B register of the night concentration position.

lVhen the night operator has to attend a local call on her position she throws key 369 inthe opposite direction to that above described. The high resistance winding of test relay 264 can now be energized if sequence switch 330reaches a position corre-' sponding to a free register set, and the connection with the operators telephone is made automatically, as described, the operator. communicates with the subscriber and sets up the wanted number on the number keys of her position. The connection takes place in the way described, the only difference being that the timing sequence switch 350, after the call has been brought in on the position, is not'started. the lefthand neighboring position, the call- ;ing lamp of such a cord is closed in a circuit over conductor 406 contact 490 top to pilot relay 358 of the night concentration position and .the lamp 372 is also lighted. lVhen the searching sequence switch 430 reaches a position in which a connection can be made with the A or B register of the night concentration position over sequence switch contacts 491, respectively 492, the high resistance winding of the test relays corresponding to relay 264 is energized over searching sequence switch contact 432, contact 486 top of sequence switch 480, contact 587 top of sequence switch 580 and upper lefthand contact of key 369. I

The disconnection of a connection established on a cord of the left hand neighboring position is made on depression of the key of this cord corresponding to the key 280. If the connection should be forcibly released the concentration operator depresses the release key of the cord corresponding to key 280 on the neighboring position and the forced release key 375 on her position, and

the release relay of such a cord is energized in a circuit over its release key, conductor 416, sequence switch contact 488 top, righthand winding of relay 362-, lefthand back contact of relay 363 and righthand contact of key 375. If a call on the cord of a neighboring position is to be brought in a second time on the same cord, the operator holds the release key on this cord and the forced release key 375 on her position depressed until the lamp on this cord which corresponds to lamp 270 is lighted. For listening in on a If a call arrives on connection of a neighboringposition theoperator depresses the listening key of the cord in question and brings her telephone in bridge to theline overthe conductors 418 and 419, contacts 484" and 4850f sequence switch-480 and the front contacts of relay 360 which is thereby energized over contact 225 is energized in a circuit including top contact 487 of sequence sw itchi480. To hinder the metering of a connectionon the neighboring position the operator depresses the hindering-metering key 364. together with release key on the cord in question. In this way the operator provides a complete supervision of the connections on theneighboring position withthe keys and apparatus provided on the concentration in exactly the same way as a connection is supervised on a home position. 1

If the A operator in a distantexchange depresses an order wire key during the-time key 369 is in the position for local service, relay 371 isfoperated in a well known manner over the order wire and locks itself up over its lefthand winding, its front contact and the lefthand lower rest contact of'key 369,whereby a signal is displayed before the operator.

1. In a telephone exchange system, the

combination with a plurality of operators positions, calling lines, meansrfor extending said lines. to said operators positions, au-

tomatic selective switches for extending said 7 linesfrom said positions, means at one of sa d positions controlled by its operator for normally preventing the extension of calls to said position, means at a second operators position; adapted to permit the extension of calls from said firstoperators position and retaining the same accessible at said second operators position, and means at said second Qoperators position for controlling all stages' of the establishment of connections' to it in the same manner as calls directly connected to said second operators position.

2. In a telephone exchange system, the

combination with a plurality of operators positions, calling-lines, means forextending sald llnes to said operators pos1t1ons,call- If a connection is to be forciblyi released on a switch 'ofthe B position the controlling means at each of said positions, means at one of said positions controlled by its operator for normally preventing the extension of calls to said position, means at a second operators position adapted to permit the extension of calls from said first operators position and retaining the same accessible at said second operators position, means at said second operators position for controlling a call connected to it over said first operators position, and means responsive to said controlling means, for connecting the call controlling means of said first operators position with the corresponding controlling means of said second operators position.

3. In a telephone exchange system, the combination with a plurality of operators positions, calling lines, means for extending said lines to said operators positions, the lines being arranged in a plurality of groups, means at one of said positions controlled by its operator for normally preventing the extension of calls to said position, means at a second operators position adapted to permit the extension of calls from said first operators position and retaining the same accessible at said second operators position, connecting circuits at each of said operators positions, a plurality of groups automatically operating switches adapted to connect said groups of calling lines with said connecting circuits, the groups of automatic switches to which the connecting circuits of said second operators position are connected being difierent from those to which the connecting circuits of said first operators position are connected, whereby the number of calling lines having access to said second operators position is increased.

4. In a telephone exchange system, the combination wlth an ordinary and a concentration operators position, calling lines, means for extending said lines to said operators positions, means at said ordinary operators position for normally preventing the extension of calls to said concentration operators position, means at said concentration operators position ad ted to permit the extension of calls from said ordinary operators position and retaining the same accessible at said concentration operators position, and means at said concentration operators position, operable at will, for

permitting said concentration operators position to serve normally as an ordinary operators position.

5. In a telephone exchange system, the combination with an ordinary and a concentration operators position, calling lines, means for extending said lines to said operators positions, means at said ordinary operators position for normally preventing the extension of calls to said concentration operators position, means at said concentration operators position adapted to permit the extension of calls from said ordinary operators position and retaining the same accessible at said concentration operators position, a manual switch at each operators position, and means at said concentration operators position, operable at will, for permitting said concentration operators position to serve normally as an ordinary operators position, operators telephone sets at each operators position, said means for permitting said concentration operators position to serve normally as an ordinary operators position being operable only when the manual switch at said ordinary operators position is operated.

6. In a telephone exchange system, the combination with an ordinary and a concentration operators position, calling lines, means for extending said lines to said operators positions, automatic switches for extending said lines from said positions, means at said ordinary operators position for normally preventing the extension of calls to said concentration operators position, means at said concentration operators position adapted to permit the extension of calls from said ordinary operators position and retaining the same accessible at said concentration operators position, and blocking means at the operators position to which a call has normally been extended, adapted to prevent the extension of other calls to such position and to be rendered inoperative at both said operators positions when said means for permitting the extension of calls is operated.

In witness whereof, I hereunto subscribe my name this 16th day of August, A. D. 1918.

LIPA PoLINKoWsKY. 

